| Honorific Prefix: | Saint |
| Adelelmus | |
| Honorific Suffix: | O.S.B. |
| Birth Date: | 11th century |
| Death Date: | 1100 |
| Feast Day: | 30 January |
| Venerated In: | Roman Catholic Church |
| Birth Place: | Loudun, Poitou, France |
| Patronage: | Burgos, Spain |
Adelelmus (died c. 1100) (French: '''Aléaume'''; Spanish; Castilian: '''Lesmes''') – was a French-born Benedictine monk venerated as a saint in the Roman Catholic Church.
Born in Loudun, Poitou, Adelelmus joined the military at a young age. During a pilgrimage to Rome he met Robert de Turlande, founder of the Abbey of La Chaise-Dieu, and left the military life for the Benedictine order.[1] He later became abbot of La Chaise-Dieu.[2]
Queen Constance of Burgundy of Castile was impressed with the reports of Adelelmus' holiness, and invited him to live in Burgos, Spain. She and King Alfonso VI founded a monastery in the city in 1079 on the condition he would be its abbot. He added a hospital and a church to the building soon after.[3] He later used his military training to help Alfonso against the Moors.[1]
After death, Adelelmus became a patron saint of the city of Burgos in Spain.[4] His remains lie in the Iglesia de San Lesmes Abad[5]
Adelelmus' feast day is kept on 30 January; it is no longer observed in the General Roman Calendar.